Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/78—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
  • B29C48/80—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
  • B29C48/83—Heating or cooling the cylinders
  • B29C48/834—Cooling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/68—Barrels or cylinders
  • B29C48/682—Barrels or cylinders for twin screws
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/78—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
  • B29C48/80—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
  • B29C48/83—Heating or cooling the cylinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/78—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling
  • B29C48/80—Thermal treatment of the extrusion moulding material or of preformed parts or layers, e.g. by heating or cooling at the plasticising zone, e.g. by heating cylinders
  • B29C48/83—Heating or cooling the cylinders
  • B29C48/832—Heating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion

Definitions

• the invention relates to a cylinder for a twin-screw extruder according to the preamble of claim 1.
• Screw extruders are used in many ways for the processing of plastics. To ensure a high quality result, it is important that the processed plastic is extruded with a temperature that is as constant as possible and in an optimal range.
• the cylinder of the extruder which is provided with a hole corresponding to the dimensions of the screw assembly, which forms the extrusion space for the plastic to be processed, is therefore usually crossed in its wall by channels through which a flowable temperature control medium (usually for cooling, if necessary. but also for heating).
• Cylinder part which has an eyeglass-like double bore (extrusion space) for the twin-screw unit, and an outer, hollow-cylindrical jacket which surrounds the inner cylinder part closely and fulfills a supporting function with regard to the forces caused by the extrusion pressure.
• Both the inner cylinder part and the hollow cylindrical jacket are in the longitudinal direction of the
• Cylindrical channels for a temperature control medium In order to be able to cool the extrusion space as effectively as possible even in the area of its thickest wall, namely in the area of the gusset hole of the spectacle bore, the cooling channels of the inner cylinder part are arranged in the area of this gusset. In the vicinity of the plane spanned by the longitudinal axes of the twin-screw unit the cooling of the extrusion space essentially through the cooling channels of the hollow cylindrical outer shell. This means that the heat must flow from the inner cylinder part into the hollow cylindrical jacket. This is hampered by the parting line between the two parts of the cylinder. Therefore one has to improve the heat transfer with more or less good success
• Cooling channel which has a course in the longitudinal direction of the cylinder which is basically similar to a helix.
• This cooling channel is arranged in the area of the separating surface between the inner cylinder part and the hollow cylindrical jacket. It is composed in the following way from Section ⁇ different shape: At the top of the inner cylinder part several equidistant grooves are milled with vertical walls in such a way that the bottom of the groove is parallel to the plane spanned by the longitudinal axes of the twin-screw unit and in its longitudinal direction is at an oblique angle to these longitudinal axes. Correspondingly, grooves are also arranged on the underside, but their alignment with the longitudinal axes is selected at exactly the opposite angle.
• the production of the cooling channel requires a comparatively high outlay, since not only the grooves on the top and Underside of the inner cylinder part must be milled, but milling work is also necessary on the inside of the hollow cylindrical shell for the production of the connecting grooves.
• the hollow cylindrical shell produced in this way can only be used for the corresponding inner cylinder part of a twin-screw extruder, but not for an inner cylinder part one
• a further solution for a cylinder of a twin-screw extruder which has an inner cylinder part and a hollow-cylindrical shell surrounding it, is known from the generic DE-OS 20 61 700.
• the wall of the inner cylinder part is characterized by numerous grooves arranged side by side above and below the B ⁇ lle ⁇ bohrung for the twin-screw unit cut in. The bottom of these grooves runs in sections in a straight line or in a circular arc in such a way that the remaining wall has an approximately equal thickness everywhere towards the extrusion space. This requires a correspondingly high thickness
• the grooves on the underside of the inner cylinder part consist of three sections, two of which run perpendicular to the longitudinal axes of the twin-screw unit and a central section is aligned obliquely to the longitudinal axes.
• the object of the present invention is to develop a cylinder according to the preamble of claim 1 for a twin-screw extruder in such a way that the manufacturing effort required for this remains as small as possible, with a particularly uniform and effective temperature of the extrusion space being ensured.
• the hollow-cylindrical shell of the cylinder is to be ensured be as universal as possible, not just for the inner cylinder part of one
• Twin-screw extruders can rather be used for both single-screw and multi-screw extruders
• the present invention is based on a twin-screw extruder with a cylinder, which encloses the twin-screw of the extruder to form an extrusion space.
• the cylinder is in turn surrounded by a hollow-cylindrical jacket, the inner surface of which is smooth-planed Extends helically in the longitudinal direction of the cylinder and can be connected to an inlet and outlet for a flowable temperature medium
• the helical channel is closed in the radial direction over part of the cylinder by separately manufactured cylinder sections, while the corresponding one Conclusion takes place in the other area of the circumference directly through the hollow-cylindrical jacket, it is provided in the cylinder designed according to the invention that the at least one channel over the entire circumference through the hollow-cylindrical nschen sheath itself is therefore no components are required that correspond to the cylinder sections from the generic state of the art.
• a considerable cost reduction for the cylinder according to the invention results from the fact that the or the channels for the temperature medium have been generated by a thread-turning process is one Particularly simple manufacturing process, which can be carried out with a clamping of the workpiece and creates channels with a completely uniform helical line, which is of great advantage for the flow with the temperature medium.
• the channel or channels therefore have no sudden kinks or other flow edges
• the cylinder can be provided with a single screw-shaped channel. In most cases, however, it will be expedient to provide several channels next to one another as in the case of a multi-start thread. Preferably three or four such channels running parallel to one another are inserted into the channel
• the slope of the channel or channels is usually kept constant over the length of the cylinder. In individual cases, however, it may be useful to change this slope in order to influence the dwell time of the temperature medium in the respective section of the cylinder along its longitudinal axis Choosing a large slope allows the temperature medium to pass faster than a smaller slope.
• the temperature medium can be guided as required by the extruder or in the opposite direction
• the webs are dimensioned in such a way that they immediately ensure a sufficient support effect for load transfer to the hollow-cylindrical jacket without it this requires separate components such as the cylinder sections according to DE-OS 2061700
• a design of the channel or channels with - seen over the circumference - different pitch depth is provided.
• the pitch depth is chosen to be the smallest in the areas in which the original wall thickness of the cylinder, ie before incorporation of the respective channel, on The greatest gait depth is provided in the areas in which the original
• Wall thickness is greatest The transition between the largest and smallest passage depth is completely smooth and even due to the thread whirling process provided for the production of the ducts.
• a cylinder is recommended in which the greatest duct depth of the duct is approximately 3 to 5 times, particularly preferably about 4 times the smallest gait depth, it may be expedient to choose the cross-sectional shape deviating from the rectangular cross-section and to provide a conical widening of the cross-section in the radial direction towards the outside.
• the width of the respective channel thus increases towards the outside means that the side faces of the respective channel in the longitudinal section through the cylinder do not run parallel to each other, but enclose an angle ⁇ .
• This angle ⁇ is advantageously in a range of 8-15 °, in particular approximately 10 °, with a conical cross-sectional shape of the channels It is advisable to choose the average thickness of the webs between two turns of the channel or channels arranged directly next to one another in the range of 1.5 to 4 times the average width of the channel or channels.
• a preferred average web width is approximately the second , 5 times the mean channel width
• a circumferential groove is worked into the cylinder into which the channels flow.
• the connections for the supply and discharge of the temperature medium are arranged on the hollow-cylindrical jacket in a corresponding manner in the region of one of the two grooves. The grooves thus come in this way
• the cylinder according to the invention ensures effective heat exchange, since the flow paths for the heat within the wall of the cylinder can be reduced as required by influencing the passage depth of the channels. Increased resistances for the heat flow as a result of the separation between individual components are used in the Invention Avoided With a given diameter of the cylinder, it is completely irrelevant for the design of the hollow-cylindrical jacket surrounding the cylinder, how many channels with which cross-sectional shape and which passage depth are respectively arranged on the cylinder
• FIG. 1 shows a perspective view of a cylinder according to the invention
• FIG. 2 shows a view from the right end of the cylinder
• FIG. 3 shows a longitudinal section like line A-A in FIG. 2 showing the upper half as a view
• FIG. 4 shows a longitudinal section like line B-B as a view
• FIG. 2 shows the lower half as a view
• FIG. 5 shows a cross section like line C-C in FIG. 3
• Fig. 6 is a view of the left end of the cylinder like Fig. 1 and
• the cylinder 1 shown in perspective in FIG. 1 is for an extruder
• twin screw unit and therefore has two partially overlapping holes for the two not shown, intermeshing screws, the holes together forming an extrusion chamber 2 with a ball-like cross-section
• a contact flange 14 is arranged, which, as in particular 3 and 4 shows that it has only a larger diameter than the cylinder 1 in its usual length.
• On the outside of the cylinder 1 numerous turns of screws are arranged in the shape of a kidney in the longitudinal direction of the cylinder 1, between which webs are partitions 4 stand
• the design of the channels 3 results in detail from the diagrams of FIGS. 3 to 5.
• channels 3 existing webs 4 is about 2- to 2! times as large as the average width of the channels 3 (measured in the longitudinal direction of the cylinder 1). From the cross section taken along the line CC like FIG. 3, which is shown in FIG. 5, it results that there are a total of four channels 3, which are aquidistant to each other in the shape of a screw over the main part of the axial length of the
• the gait depth of the channels 3, that is to say their depth in the radial direction of the cylinder 1 is not constant over the course of the circumference of the cylinder 1, but changes uniformly in the vicinity of the through the longitudinal axes of the Extrusion space 2 spanned plane, in which the wall of the cylinder 1 has the smallest value, there is also the narrowest pitch, which is denoted by h, offset by 90 ° to this, that is, in the gusset area of the glasses-like bore, the cylinder 1 has its greatest wall thickness There, the passage depth of the channels 3, denoted by h 2 , is also the greatest. The uniform change in the passage depth between the greatest value h 2 and the smallest value h- is obtained in a simple manner by corresponding
• FIG. 3 shows the side view and the longitudinal section in the region of the greatest passage depth h 2
• FIG. 4 shows the longitudinal section that is preferably shown in FIG. 2 along the line BB and is offset by 90 ° , So a longitudinal section in the area of the smallest passage depth h-, By Va ⁇ ist the passage depth over the circumference of the cylinder 1 it is achieved that the extreme over the circumference of the cylinder 1 differences in the heat flow path between the extrusion chamber 2 and the channels 3 are significantly reduced
• a total of four channels 3 each flow into a circumferential groove 7 or 8 which is arranged near the front ends of the cylinder 1 and which functions as a distributor or one
• FIG. 6 shows a view of the end face of the cylinder 1 with the contact flange 14.
• FIG. 2 shows a view of the end face of the cylinder 1 with the contact flange 14.
• Fig. 7 shows half in longitudinal section the assembly of a solid cylinder 1 1, which is formed from the cylinder 1 and the associated hollow cylindrical jacket 10.
• the hollow cylindrical jacket 10, which has a connecting flange 17, 18 on each of its end faces, has a smooth surface on its inside.
• the inside diameter of the hollow cylindrical jacket 10 corresponds to that
• the temperature control medium After flowing through the channels 3, the temperature control medium enters the circumferential groove 8, which acts as a collector, and is withdrawn from there via the recess 19 and the derivation 13 from the full cylinder 11. During the flow through the channels 3 there is an effective heat exchange between the temperature control medium and the extrusion space 2.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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ID=7920123

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (6)

Citations (2)

Family Cites Families (26)

• 1999
  • 1999-08-24 DE DE19941160A patent/DE19941160B4/de not_active Expired - Fee Related
• 2000
  • 2000-08-04 DE DE20013882U patent/DE20013882U1/de not_active Expired - Lifetime
  • 2000-08-17 TW TW089116667A patent/TW469218B/zh not_active IP Right Cessation
  • 2000-08-22 JP JP2001518242A patent/JP4610826B2/ja not_active Expired - Lifetime
  • 2000-08-22 WO PCT/DE2000/002896 patent/WO2001014121A1/de active IP Right Grant
  • 2000-08-22 CN CNB008118876A patent/CN1190310C/zh not_active Expired - Lifetime
  • 2000-08-22 EP EP00963931A patent/EP1206341B1/de not_active Expired - Lifetime
  • 2000-08-22 US US10/069,218 patent/US6805480B1/en not_active Expired - Lifetime
  • 2000-08-22 DE DE50009494T patent/DE50009494D1/de not_active Expired - Lifetime

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